Transcriber's Note:
Minor errors in punctuation have been corrected without note.
The following typographical errors in the original have been corrected:
P. 110: 'a panopoly of gadgetry': corrected to panoply
P. 113, caption to Figure 13: 'Feuss': corrected to Fuess
Footnote 28: 'Gewerbeaustellung': corrected to Gewerbeausstellung
Footnote 28: 'Physikalisches Worterbuch': corrected to Wörterbuch
Footnote 29: 'see also Gerland and Traümuller': corrected to Traumüller